Search plugin is an easy way to include search into your application. Using this plugin you will able to have paginable search in any controller. Plugin support simple methods to search inside models using strict and non-strict comparing, but also allows you to implement any complex type of searching.

The users plugin is for allowing users to register and login manage their profile. It also allows admins to manage the users.
The plugin is thought as a base to extend your app specific users controller and model from.
That it works out of the box does not mean it is thought to be used exactly like it is but to provide you a kick start. You will have to extend the plugin on app level to customize it. Read the how to use it instructions carefully.

The Migrations plugin provides a comprehensive management system whereby the database schema for a CakePHP project can fluctuate during development involving any number of developers. This is achieved by incrementally managing database changes, providing customisable hooks and callbacks for data migration and changes to meet migration paths, and migration maps to provide flexible application of migration instances.

The tags plugin includes the Taggable Behavior that allows you to simply tag everything. It saves all tags in a tags table and connects any kind of records to them through the tagged table. You can specify alternate tables for both in the case you get *A LOT* records tagged.